Children with fever and bad breath may be caused by viral infection of the upper respiratory tract infection, usually manifested as cough, runny nose, fever and other symptoms, the upper respiratory tract infection leads to a weakened digestive function of the child’s gastrointestinal tract, indigestion or accumulation of food, so the child will be accompanied by bad breath, at this time, parents are advised to take the child to the hospital for examination and appropriate treatment, so that the child usually eat some good digestive food, such as Green leafy vegetables, thin rice, etc. In addition, when a child has a fever, the saliva secretion in the mouth will be reduced and the bactericidal effect of saliva will also be inhibited, so the food residues left in the mouth will produce an unpleasant smell under the fermentation of bacteria. So when the child has a fever, parents can let the child drink more water, both to reduce the child’s body temperature can also achieve the purpose of cleaning the mouth, and let the child eat some fresh fruit to stimulate the secretion of saliva, can relieve the child’s fever mouth smelly situation. In ordinary life, parents should let their children develop the habit of brushing, flossing and rinsing after meals, and brushing the tongue, which can remove the food residue and bacteria covering the tongue, in addition, parents should take their children for regular oral checkups to see if there are oral diseases such as dental caries.